To start, Lear himself asks his love from his two eldest daughters, Gonoreil and Regan. Both are equally vicious and conniving, equally vying for the attention of the Earl of Gloucester's son, Edmund. Lear's downfall is that he is used to so much power, that he would demand the same great amount of respect.
Gloucester suffers more of less of the same fate than the ill-fated title character. Rather than placing his love into his legitimate son, Edgar, he gives it to his iligitimate son Edmund who offers him no love in return. So how is Gloucester awarded for his affections? He has his eyes gouged out, blinded literally as Lear is blinded metaphorically on how his daughters are nothing but two-faced wolves in sheep's clothing.
It is a sad fact that Lear and Gloucester are representatives of parents who place their faith on the "wrong" children, the children with the potential of betraying them. You have Cordelia, who is the one who truly loves her father but he keeps pushing her away. Gloucester is not appreciative of his son Edgar, who shows more valor than what Edmund was ever capable of. It is no wonder that both fathers are kicked out of their own establishment.